Method of handling and assorting sheets



Aug. 3, 1954 2,685,359

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fiz'iflih/m y Patented Aug. 3, 1954 METHOD OF HANDLING AND ASSORTING SHEETS Rollin D. Osgood, Birmingham, Ala, assignor to United States Steel Corporation, a corporation of New Jersey Original application December 3, 1947, Serial No. 789,403. Divided and this application February 16, 1951, Serial No. 211,284.

(Cl. l9833) 2 Claims.

This invention relates to improved methods of handling and assorting metal sheets immediately following a plating operation.

The present application is a division of my earlier application, Serial No. 789,403, filed December 3, 1947, and assigned to the same assignee, which application issued as Patent No. 2,564,027, August 14, 1951.

The methods of the present invention are especially suited for handling and assorting steel sheets that have been tin plated by hotdip processes. Therefore the invention is described in connection with a hot-dip tinning line, but it is to be understood that the invention is not necessarily limited to such application.

The usual practice in hot-dip tinning includes passing steel sheets in multiple parallel rows through molten tin metal, hot palm oil and then through a branner, which removes all excess oil and polishes the tinned sheet. The tinned sheets are then transported to an assorting room, where they are visually inspected and assorted as primes, menders, and waste-waste. Prime sheets are counted and stacked for shipment; menders are reprocessed to form primes, while waste-waste sheets are sold as an off grade product.

In usual installations with which I am familiar, operations performed subsequent to tinning are largely manual, and consequently are time 0011- suming and costly. Each sheet is handled individually during inspection and prime sheets are counted and stacked by hand. During tinning, the trailing or list edge of each sheet becomes slightly thicker than the leading edge since a little more tin accumulates at the trailing edge. Consequently the workman who counts and stacks the sheets must stack them with the trailing and leading edge of each few sheets alternated in order to form a uniform stack.

An object of the present invention is to provide improved methods for handling and visually and digitally inspecting sheets subsequent to plating wherein manual operations are substantially eliminated.

A further object of the invention is to provide improved methods of operating a double hot-dip plating line in which inspection of the sheets is preceded by consolidating a pair of rows of plated sheets into a single row with the leading and trailing edges of every other sheet reversed,

. whereby only one inspector and one inspection apparatus can inspect and assort a double line and the prime sheets are ready for piling evenly. A further object of the invention is to provide improved methods for continuously assorting sheets as primes, menders, and waste-waste and arranging alternated sheets with the original leading and trailing edges reversed.

In accomplishing these and other objects of the invention I have provided improved details of construction, a preferred form of which is shown in the accompanying drawings wherein:

Figure 1 is a top plan view of a portion of a hot-dip tin plating line following the plating equipment and adapted to be operated in accordance with the method of the present invention;

Figure 2 is a side elevational view of the line, partly in section, the View being taken on line 11-11 of Figure 1;

Figure 3 is an enlarged top plan view of a preferred construction of heet transfer apparatus;

Figure i is an end elevational view of the transfer apparatus in the direction of arrow 4 in Figure 3;

Figure 5 is a vertical sectional view of the transfer apparatus taken substantially on line VV of Figure 3;

Figure 6 is a horizontal sectional view of the transfer apparatus taken substantially on the line VI-VI of Figure 5;

Figure 7 is an electric wiring diagram of the control circuit for operating the transfer apparatus;

Figure 8 is an enlarged top plan view of a preferred construction of inspection apparatus;

Figure 9 is an enlarged side elevational view of the inspection apparatus;

Figure 10 is a vertical sectional view of the inspection apparatus taken substantially on line XX of Figure 8;

Figure 11 is a vertical sectional view of the drive mechanism for the inspection apparatus taken substantially on line XI-XI of Figure 8;

Figure 12 is a vertical sectional view of the drive mechanism for the inspection apparatus taken substantially on line XII-XII of Figure 11; and

Figure 13 is an electric wiring diagram of the control circuit for operating the inspection, ap-

paratus.

Figures 1 and 2 show branner rolls it of hotdip tin plating equipment from which plated sheets S emerge for asserting and stacking. Sheets emerge from the plating equipment in two parallel rows and pass onto parallel horizontal conveyor belts l5 and i6. Said conveyors are supported on a frame ii and are driven from a horizontal shaft I8 journalled in the lower portion of said frame, Shaft i8 is driven from branner roll is by a chain I9; and drives the conveyors through chains 20 and 2|, Figure 3.

The feeding rate is such that sheets on conveyor is are spaced by a little more than the length of an individual sheet. A transfer apparatus 22 lifts the sheets individually from conveyor i and places them on conveyor 66 within this space to form a consolidated single row of sheets on conveyor Hi. The sheets in said single row are spaced at relatively close and substantially uniform intervals. The details of the transfer apparatus are fully described hereinafter.

From conveyor l6 sheets pass onto a conveyor 23, which is formed of a series of transversely spaced parallel belts 23. Said belts are supported on a frame '25, which has rearward rollers 26, intermediate rollers 27 and forward rollers 28 over which the belts pass. The axis of intermediate rollers 21 coincides with the axis of an inspection wheel 29 hereinafter fully described. Conveyor 23 is driven by a motor 30 which is supported on frame 25 and is operatively connected with the forward rollers 28.

From conveyor 23 the sheets traverse a series of conveyors which carry them past reject gates and to a mechanical counter and piler. The gates, counter and piler are of any suitable known construction. The mechanism beyond conveyor 23 is not per se a part of the present invention; hence its construction is not shown nor described in detail.

The operator visually and digitally inspects sheets as they pass inspection wheel 29, where their travel is temporarily arrested. In accordance with known practice, the operator closes a switch as he detects a mender sheet and a different switch as he detects a waste-waste sheet. Closing said switches operates respective reject gates after a suitable timed interval such I that the defective sheet is rejected to the proper group. Inasmuch as time delay mechanism for operating reject gates is known and per se is ,not part of the present invention, such mechanism is not shown nor described in detail.

The original leading and trailing edges of sheets transferred from conveyor E5 to conveyor 16 are reversed from the corresponding edges of untransferred sheets so that, except for sheets rejected, the original leading and trailing edges of alternate sheets are reversed in the final stack. r

The rejection of a few sheets does not appreciably affect uniformity of the stack, and any unevenness tends to be compensated, since rejection may come from sheets originating from either row.

The mechanical construction of the transfer apparatus 22 is shown in detail in Figures 3, 4, 5, and 6. The apparatus comprises a fixed frame 32 that straddles conveyors i5 and I6 and their supporting frame ll. Said frame includes uprights 33 and as at opposite sides of said conveyors and cross beams 35 and 3B fixed to said uprights and connected by short longitudinal members 3'5.

Frame 32 supports a magnetic turntable 38 and drive means therefor. As sheets emerge on conveyor I5, they engage and momentarily close a trigger switch 39, which actuates the turntable magnets to lift a sheet from the conveyor. At the same time the drive means for the turntable is actuated, whereupon the turntable automatically rotates through a substantially semi-circular arc and deposits the sheet on conveyor 55.

As shown in Figures 3 and 4, the drive for the turntable includes a motor 40 supported on cross beams and 36. Motor 48 runs continuously and drives a worm ll, which drives a worm gear 42, Figure 5. The worm and worm gear are mounted within a fixed housing 33 supported above beams and 35 by legs is and 55.

Worm gear i2 is fixed to a vertical shaft 48, which carries an annular drivin magnet ll of a magnetic clutch at its lower end. The upper end of shaft :35 carries a pair of slip rings 48 and it-3 for conducting current to the driving magnet 4?. Driving magnet i? is thus continuously rotated and, as hereinafter explained, it may be intermittently energized through slip rings 48 and 49. An annular braking magnet is fixed between beams 35 and 36 beneath driving magnet tll and is axially aligned with shaft 45.

A vertical shaft 51, axially aligned with shaft 38, is journaled in antifriction bearings 52 and 53. Said bearings are fixed to beams 35 and 36 and permit shaft 5! to have limited axial movement. A clutch plate 54 of magnetic material is fixed to the upper end of shaft 5! in the space between driving magnet Q7 and the braking magnet 56. Turntable 38 is fixed to the lower end of Turntable 38 carries electric transfer magnets 55 and 55 in diametrically opposed positions at opposite sides of said shaft. As shown in Figure 4, the lower faces of magnets 55 and 56 are close to the upper faces of conveyors l5 and IE, but the clearance is sufficient not to interfere with sheet movement. In order to lift thin sheets, magnets 55 and 56 preferably extend radially from a point above the center of each sheet and have elongated radially extending poles.

As best shown in Figures 5 and 6, shaft 51 carries a cam ring 5? and slip rings 58 and 59 at its intermediate region between bearings 52 and 53. The cam ring has two segments of increased radius 180 apart, one of which is shown at as. Said segments operate a cam switch Bl to deenergize magnets 55 and 56 to deposit sheets on conveyor Hi. The slip rings conduct current to magnets 55 and 58. The purpose and operation of these elements is more fully explained hereinafter in the description of the electric circuit.

For supporting cam switch Bl, frame member 35 carries a fixed bracket 62 on which is supported an arcuately adjustable yoke 53. Said yoke carries switch 6|, which has a roller 64 that rides against the surface of cam ring 51, Figure 6. Cam switch 5} is normally closed, but is opened momentarily while roller 64 engages one of the projecting segments of cam ring 51.

Slip ring 58 comprises two substantially semicircular segments 55 and 66 separated by insulators El and 68, Figure 6. Yoke 63 carries a pair of brushes 59 and lil engaging segments 55 and 6'5, the brushes preferably being mounted for arcuate adjustment with respect to the yoke. Slip ring 59 is circular and continuous, and yoke 63 carries a brush H which contacts slip ring 59.

A downwardly depending boss 12 is fixed to yoke 63 and has a transverse threaded bore. A threaded spindle 13 is journaled in a fitting it which is pivoted to bracket 62, as indicated at 15, Figure 6, to permit arcuate movement of the spindle. Said spindle is threadedly engaged within the transverse bore through boss 12 and carries a knob 16 accessible externally of the apparatus. Thus rotation of knob 16 adjusts yoke 63 arcuately about vertical shaft 51.

Figure 7 shows the control circuit for operating the transfer apparatus. The circuit includes '71 and i8 and contains relay coil C, contacts Bi and cam switch 6!. A conductor BI is connected to conductor 1! and to conductor 89 shunting relay coil C and contacts Bl. Conductor 8! contains relay coil A and trigger switch 39 which, as Figure 3 shows, is positioned in the path of sheets on conveyor I5 so that it closes momentarily as each sheet passes on said conveyor.

Closing of the trigger switch energizes relay 'coil A, since cam switch BI is normally closed.

Energization of relay coil A closes contacts AI which seals in relay coil A, shunting trigger switch 39. At the same time, contacts A2 close and establish a current path to segment 65 of slip ring 58 via a conductor 82 and brush 69. Transfer magnet 55 is connected between segment 65 and slip ring 59. Brush H, which contacts slip ring 59, is connected to conductor 78 through a conductor 83. Thus when contacts A2 are closed, the transfer magnet 55 is energized via conductor l1, contacts A2, conductor 82, brush 69, slip ring segment 65, magnet 55, slip ring 59, brush H, conductor 8-3 and conductor 18. Magnet 55 thereupon lifts the sheet from conveyor l5.

Closing of contacts A2 also completes a circuit to relay coil B through normally closed relay contacts DI and through a conductor 84 connected to the conductor 89 intermediate coil C and cam switch 6!. Energization of coil B closes contacts Bl in conductor 8!] and thereby energizes relay coil C. Energizing coil C closes contacts Cl, which seal in coil B via contacts A2 and Cl, thus shunting contacts D].

At the same time, energizing coil C closes contacts C2 which are in conductor TI. The terminus of conductor H is connected to a brush 85 that engages slip ring 48 at the top of vertical shaft 46. Said slip ring is connected to the driving magnet 37 and the opposite end of said driving magnet is connected to slip ring 49. The terminus of conductor 18 is connected to a brush at that engages slip ring is. Energization of coil C also opens contacts C3 which are in a conductor 8i which extends between conductors Ti and i8 and contains the braking magnet 5c. Thus the driving magnet 47 is energized and lifts clutch plate 5'2, whereupon shaft 5! and turntable 38 commence to rotate.

Rotation of shaft 5| rotates slip ring 58 in the direction indicated in Figure 7. After said slip ring is rotated a predetermined distance, brushes 69 and it both contact the same segment 55, which forms a current path between them. Brush H3 is connected by a conductor 88 6. closed for a predetermined interval and then opens the circuit. Inasmuch as such timing mechanism is known and per se does not form a part of the present invention, the details are not shown. Energization of coil D opens contacts DI and closes contacts D2, the latter sealing in the circuit through timer 89 and coil D.

Continued rotation of shaft ii moves one of the projecting cam segments cc to a position where it momentarily opens cam switch 6|.

Opening this switch breaks the circuit through conductor and thus deenergizes coils A, B, and C, whereupon the contacts C2 open and interrupt the circuit to the driving magnet 41. Contacts D2 remain closed and contacts C3 are closed by deenergization of coil C. Thus the circuit to the braking magnet S is closed. The arrangement is such that cam switch 6! opens about 5 before turntable 3t has rotated 183 so that the turntable comes to rest after rotating exactly 180. Necessary adjustments in the point at which the turntable stops can be made through adjustment of spindle i3, which varies the posttion of the cam switch with respect to the 180 point.

The transfer magnets are kept energized momentarily after the turntable has stopped. The circuit by which they are energized at this time is via conductor 77, contacts D2, conductor 88, brush Ell, segment 85, magnet 55, slip ring 59, brush H, conductor 33, and conductor 78. As soon as the predetermined interval has elapsed, timer opens the circuit to coil D, which opens contacts D2 and thereby deenergizes the transfer magnets. The magnets thereupon deposit the sheet on conveyor It. The apparatus is now in position for the opposite transfer magnets 56 to move a sheet from conveyor 55 to conveyor [6 and the cycle of operations just described is repeated, except that magnets 5%, segment 66 and the other cam segment 53 are now operative.

Preferably the braking magnet 59 is shunted by a high resistance $2 and a condenser 93, and the driving magnet il is shunted by a similar resistance and condenser 5:3 and respectively. The purpose of these shunts is to prevent arcing when the circuits to the magnets are broken. This type of shunting arrangement is a known device for preventing arcing and hence is not described in detail.

Preferably a push button position switch 95 is connected around trigger switch S8 and cam switch 5! so that the apparatus can be energized manually for testing and adjustment. It is seen that closing switch 35 has the same effect as closing trigger switch 3%.

' The mechanical details of the inspection wheel 29 are best shown in Figures 9, 10, 11, and i2. Said wheel comprises six sets of radial spokes 98 fixed to hubs 99, the spokes of each set being parallel with each other and spaced 60 from the adjacent set. Hubs are fixed to a horizontal shaft sec and spaced longitudinally of said shaft so that a set of spokes is positioned between each pair of belts 26 that make up eonveyor 23. Intermediate the hubs, shaft ltd carries the rollers 2'! over which pass belts 2d of conveyor 23. Shaft N38 is journaled in bearings I 0! and I92 fixed to frame 25. Drive mechanism is provided so that each sheet entering the wheel from conveyor 23 momentarily closes a trigger switch W3 and rotates wheel 2Q through an angle of 60.

The sheet that has entered the wheel thereupon is moved to the position shown in full lines "in Figure 10 and its travel temporarily arrested.

inspected sheet is picked up by the forward section of conveyor 23 and carried to the piler or diverted by one of the reject gates.

The adjustment of wheel 29 is such that the wheel comes to rest following each 60 advance when the spokes in the forward and rearward positions are horizontal. As shown in Figures 9 and 10, in the position of rest the upper faces of the rearward spokes are slightly below the upper faces of belts 24 of conveyor 23 in order that sheets entering the wheel do not scrape across the spoke faces. Preferably the forward section of conveyor 23 is downwardly inclined at an angle such that the forward section is intermediate two sets of spokes when the wheel is stopped. As the sector of the wheel containing an inspected sheet rotates past the inclined for ward section, said section picks up the sheet and the spokes move cleanly away so that again there is no scraping.

Sheets deposited on the downwardly inclined conveyor section tend to slide down said section, and thus to upset timing of the reject gates. In order to prevent such sliding, magnets I94 are arranged underneath the beits of the inclined conveyor section, preferably being permanent magnets and encased in suitable fixed housings I 65.

As shown in Figure 10, the intersection of adjacent sets of spokes 98 is preferably at a sharp angle and the faces of the spokes preferably form a substantially plane surface. This arrangement is desirable in order to keep the sheet flat while undergoing inspection so that it does not distort light reflections. Thus the inspector is enabled to determine more accurately whether there are imperfections in the sheet.

The inspection wheel is preferably driven by a magnetic clutch arrangement similar to that for driving the transfer apparatus. The drive is from a motor IE8 which is supported on frame 25 and continuously drives speed reducing gears IBI through a suitable coupling, Figure 8. Gears I07 continuously rotate a shaft I68, the inner extremity of which carries an annular driving magnet I89 of the magnetic clutch, Figure 11.

A horizontal shaft Hi3, axially aligned with shaft I88, is journaled in suitable bearings III and H2 on frame 25 and has limited axial movement. The outer end of shaft HE carries a clutch plate H3 adjacent driving magnet I69. An annular braking magnet I M is positioned adjacent clutch plate H3 on the opposite side from side driving magnet.

Shaft Hli carries a pinion H5 which meshes with a gear H6 on shaft I on which hubs 39 of wheel 25 are mounted, Figure 8. Preferably the ratio of pinion H and gear H6 is l to 6 so that each whole revolution of shaft H0 rotates Wheel 29 through an angle of 60.

Shaft H0 carries a cam ring Ill which has an enlarged sector I I8, Figures 11 and 12. A bracket H9 is fixed on a base I 20 beneath said cam ring and supports an arcuately adjustable yoke I2I. Said yoke carries a normally closed cam switch I22, which has a cam follower I23 riding against said cam ring. Switch I22 is opened momentarily as the enlarged sector H8 of the cam ring engages cam follower I23.

The mechanism for adjusting yoke I2I includes a threaded spindle I2t which is journaled in a fitting I25 that is pivoted to bracket H9, as indicated at 126, Figures 11 and 12. The yoke has a projecting boss I21 that has a transverse threaded bore that receives the threaded portion of spindle I2 3. Thus rotation of said spindle adjusts yoke 42! about the axis of shaft III]. This adjustment varies the position at which cam sector HS opens cam switch I22 and thus controls the angular position at which wheel 29 comes to rest.

The outer extremity of shaft I98 carries slip rings I28 and I29 which conduct current to the driving magnet I29, Figures 8 and 11.

The control circuit for operating the inspection wheel is shown in Figure 13. The circuit includes conductors I53 and I3I connected to a suitable outside power source. Preferably said conductors include a master switch I32 for manually opening and closing the circuit. Conductors I36 and i are connected through a conductor 133 that contains trigger switch I03, cam switch I22 and the coil of a relay E. Closing of trigger switch I63 energizes coil E since cam switch I22 is normally closed.

Energization of coil E closes contacts Ei which seal in coil E. Contacts E2 are also closed and complete a circuit to the driving magnet I 09 via a conductor I36, a brush I35, slip ring I28, driving magnet Hi9, slip ring 529, a brush 36, and a conductor I37 to conductor i3I. At the same time, normally closed contacts E3 open and thus interrupt the circuit to braking magnet II i. Thus shaft II It and inspection wheel 23 are set in motion.

Continued rotation of shaft HS moves cam II! to a position where its enlarged sector H3 opens cam switch E22, whereupon the circuit to coil E is broken. Contacts E2 open, interrupting the circuit to the driving magnet, and contacts E3 close, completing the circuit to the braking magnet. The adjustment of yoke I2I is such that shaft H3 stops after one complete revolution, which is equivalent to /6 of a revolution of the inspection wheel.

Preferably the driving magnet IE9 is shunted by a relatively high resistance I58 and a condenser IS9 and the braking magnet 5 M is shunted by a similar resistance and condenser MI and MI respectively. The resistance and condenser prevent arcing similar to corresponding elements in the transfer apparatus circuit.

Preferably a jog relay J and double pole jog push button switch I42 are provided for rotating inspection wheel 29 by manual actuation when desired. Jog relay J is connected across conductors I38 and I SI in a conductor M3. Switch I42 has a first pair of poles I i-4 in conductor I43 and a second pair of poles M5 in a parallel conductor it, which also contains normally closed contacts JI.

Closing of switch I42 completes a circuit to coil E via conductor M6, poles Hi5 and normally closed contacts J I. Energization of coil E closes contacts EI which seal in coil E through cam switch I22. Contacts Ed in conductor Hi3 thereupon close, and poles Hit of switch I42 close at the same time poles I45 close and complete a circuit through jog relay coil J.

Completing this circuit closes contacts J2 which seals in coil J as long as pushbutton I42 is held closed. When relay coil J is energized, contacts J I open, breaking the circuit through switch M2 and contacts J l through coil E. When cam switch I22 opens, coil E is deenergized and opens, stopping the inspection wheel. Thus switch I42 must be opened and reclosed to operate the inspection wheel manually another notch and another spoke.

From the foregoing description it is seen that the method of the present invention consolidates multiple rows of sheets from the plating equipment into a single row. The original leading and trailing edges of alternate sheets in the single row are reversed so that the sheets can be stacked uniformly as they come from the row. Consolidation of the multiple rows enables inspection and assorting to be conducted from a single station without interrupting continuous movement of the line. Thus the transfer step and the inspection step cooperate and form a novel combination that makes possible continuous assorting and stacking of sheets from a multiple line without additional handling.

While I have shown and described but a single embodiment of the present invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited by the disclosure set forth but only by the scope of the appended claims.

I claim:

1. In the handling of hot-dip tin plated sheets which emerge from tinning equipment, the leading edges of all of said sheets at the start being thinner than the trailing edges thereof, a method of assorting and uniformly piling prime sheets comprising arranging all of said sheets as they emerge from the tinning equipment in a closely spaced single row, reversing the leading and trailing edges of alternate sheets from their original position as they are arranged in said single row,

conveying said single row of sheets past an inspection station, conveying the inspection sheets from said station toward a prime sheet piler, diverting defective sheets observed at said station from the row ahead of said piler, and piling the remaining prime sheets at said piler with the thinner and thicker edges of adjacent sheets in the resulting pile reversed except for missing defective sheets.

2. In the handling of hot-dip tin plated sheets which emerge from tinning equipment in two parallel rows, the leading edges of all of said sheets at the start being thinner than the trailing edges thereof, a method of assorting and uniformly piling prime sheets comprising consolidating the two rows of sheets into a continuous closely spaced single row, reversing the leading and trailing edges of alternate sheets from their original position as they are placed in said single row, conveying said single row of sheets past an inspection station, conveying the inspected sheets from said station toward a prime sheet piler, diverting defective sheets observed at said station from the row ahead of said piler, and piling the remaining prime sheets at said piler with the thinner and thicker edges of adjacent sheets in the resulting pile reversed except for missing defective sheets.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,305,561 Paridon June 3, 1919 1,535,031 Nevins Apr. 21, 1925 1,789,253 Parker Jan. 13, 1931 1,846,776 Werner Feb. 23, 1932 1,998,806 Eggleston Apr. 23, 1935 2,000,292 Miller May 7, 1935 2,501,224 Kadell Mar, 21, 1950 2,549,772 Carroll Apr. 24, 1951 2,581,598 Parker Jan. 8, 1952 

